Servo Drives FAQ's

Answer:

1.Enable ASDA-Soft version V4.XX or V5.XX, click [Tools] and select [MSizing Tool] from the drop-down menu to open the [MSizing Tool] dialog window.

You will see seven types of transmission devices for the motor's mechanism in the left side of the [MSizing Tool] dialog window. You can choose the type of transmission device first and input its specifications, such as screw pitch, great ratio, max. moving speed, acceleration, deceleration and other required data or conditions.

3.The right side of the [MSizing Tool] dialog window consists of four major functions: the User Input Parameter tab, the Motor Specific tab, the Density Table tab, and the Properties tab. Click on the corresponding tab to access its functions. The User Input Parameter tab is the default tab. In the User Input Parameter tab, you may define the required parameters according to your application needs. In the Motor Specific tab, you can search all of Delta's servo motor specifications listed here for your reference. In the Density Table tab and Properties tab, you can use optional settings to further define the required servo motors. For example, if you set the max. motor load inertia ratio to 15, it means the load should have no more than 15 times the moment of inertia of the motor rotor that is driving it. When matching motor to load, doing this allows for safe sizing over a wide range of applications.

4.When you click the 'Calculate' button, the MSizing Tool function calculates the motor specifications, such as torque, speed, and inertia requirements and processes all motor data from the database and then generates the calculation process and calculation result and then creates a list of all motors that match your application specifications.

Answer:

The explanation of symbols marked after parameter codes are shown as the following. Please pay close attention to it before setting these parameters.
(★) Read-only register, such as P0-00, P0-01, P4-00.
(▲) Parameter cannot be set when Servo On (when the servo drive is enabled).
(●) Parameter is effective only after the servo drive is restarted (after switching power off and on), such as P1-01.
(■) Parameter setting values are not retained when power is off.

Q11: How to monitor the status of the servo drive via the digital keypad?
A11:
The users can use parameter P0-02 directly to specify the monitor status and change it via UP and DOWN key on the keypad. When the power is applied, the monitor status depends on the setting value of P0-02. For example, if the setting value of P0-02 is 2 when the power is applied, the monitor function will be Pulse counts of pulse command, the C.P monitor codes will first display and then the pulse number will display after.

P0-02 Setting

Display Message

Description

Unit

0

Motor feedback pulse number (Absolute value)

[pulse]

1

Motor feedback rotation number (Absolute value)

[rev]

2

Pulse counts of pulse command

[pulse]

3

Rotation number of pulse command

[rev]

4

Position error counts

[pulse]

5

Input frequency of pulse command

[kHz]

6

Motor rotation speed

[rpm]

7

Speed input command

[V]

8

Speed input command

[rpm]

9

Torque input command

[V]

10

Torque input command

[%]

11

Average load

[%]

12

Peak load

[%]

13

Main circuit voltage

[V]

14

Ratio of load inertia to Motor inertia

[times]

15

Motor feedback pulse number (Relative value) / Position latch pulse number

[pulse]

16

Motor feedback rotation number (Relative value) / Position latch rotation number

[rev]

Answer:

There are five groups for drive parameters, which are:
Group 0: Monitor parameter (example: P0-xx)
Group 1: Basic parameter (example: P1-xx)
Group 2: Extension parameter (example: P2-xx)
Group 3: Communication parameter (example: P3-xx)
Group 4: Diagnosis parameter (example: P4-xx)

Answer:

The users can select the adequate regenerative resistors according to the allowable frequency required by actual operation and the allowable frequency when the servo motor runs without load. The allowable frequency when the servo motor run without load is the maximum frequency that can be operated during continuous operation when servo motor accelerate from 0rpm to rated speed and decelerate from rated speed down to 0rpm. The allowable frequencies when the servo motor run without load are summarized in the following table.

Servo Motor Models

Allowable frequency when the servo motor run without load (times/min)

100W

200W

400W

750W

1.0kW

1.5kW

2.0kW

3.0kW

01

02

04

07

10

15

20

30

ASMT L Series

12133

2022

1071

337

140

100

155

63

ASMT M Series
-
-
-
-
136
93
104
38

When the servo motor runs with load, the allowable frequency will change according to the changes of the load inertia and rotation speed. Use the following equation to calculate the allowable frequency. 
 
m = load/motor inertia ratio
The users can select the adequate regenerative resistors according to the allowable frequency by referring to the table below:

Allowable Frequency (times/min)

ASMTL Series

ASMTM Series

100
W

200
W

400
W

750
W

1000
W

1500
W

2000
W

3000
W

1000
W

1500
W

2000
W

3000
W

01

02

04

07

10

15

20

30

10

15

20

30

BR400W040

-

-

7137

2247

933

674

-

-

913

621

-

-

BR1K0W020

-

-

-

-

2333

1685

1291

523

2282

1552

863

315

Answer:

1) When the output torque of servo motor in reverse direction of motor rotation speed, it indicates that there is a regenerative power returned from the load to the servo drive. This power will be transmitted into the capacitance of DC Bus and result in rising voltage. When the voltage has risen to some high voltage, the servo system needs to dissipate the extra energy by using a regenerative resistor. 
2) Delta ASDA series servo drive provides a built-in regenerative resistor and the users also can connect to external regenerative resistor if more regenerative capacity is needed. When using an external regenerative resistor, connect it to P and C, and make sure the circuit between P and D is open. When using a built-in regenerative resistor, connect it to P and D, and ensure an open circuit between P and C.
3) When the regenerative power exceeds the processing capacity of the servo drive, the fault, ALE05 may occur. At this time, please install an external regenerative resistor.

Answer:

Maybe the following conditions are not met. When estimating the ratio of load Inertia to servo motor inertia, please satisfy the following conditions in order to ensure the correct ratio of load Inertia to servo motor inertia.
1) The accel. and decel. time for reaching 2000rpm should be 1sec. and below.
2) The rotation speed should be kept as 200rpm and above.
3) The load inertia cannot exceed 100-multiple of motor inertia.
4) The outside force cannot too much and the change of the ratio of load inertia to servo motor inertia cannot be excessive.

Answer:

Stiffness is a measure of how well a servo motor can hold a position when some outside force is trying to move it. We can say it is a strength that is against the low frequency external force.

Answer:

Ratio of load inertia to servo motor inertia: (J_load /J_motor)
J_load: Load inertia 
J_motor: Motor rotor inertia 
When selecting the servo drives and motors that the user want to use, the user not only should consider the motor torque and rated speed, but also need to know the ratio of load inertia to servo motor inertia. Then, the user can select the proper motor that is correctly matched for the servo drive according to the actual requirements of the connected machine (load condition) operation and the quality and quantity requirements for materials processing and manufacturing. When perform tuning and trial run, setting (J_load /J_motor) correctly is the most important / essential for optimizing the performance of the mechanical system and servo system and make them work efficiently.